The invention relates to a control device for DC motors which are provided with a commutator for feeding their motor windings which has at least four sliding contacts, the control device comprising a modulation stage which generates at least one control signal which is modulated as to pulse width with a clock frequency substantially above the motor speed and a control circuit which is controlled by the at least one control signal and has at least one load branch which feeds the commutator and is provided with an electronic switch controlled by the control signal modulated as to pulse width.
Control devices of this type are not known from the state of the art, wherein the entire commutator with all the sliding contacts of the DC motor is always controlled by a single load branch.
A load branch of this type is to be dimensioned in accordance with the power of the electromotor, wherein the control device, in particular, must be designed such that it bears the freewheeling current which occurs and that the reactive effect of the pulse width modulation on a power system feeding the control device is as small as possible.
The object underlying the invention is to design a control device as inexpensively as possible.